I've been cooking professionally now for almost ten years.  Over these years I've acquired hundreds of cookbooks.  Here is a list of my top '5' of all time.  

In no particular order 

Michel Bras- Essential Cuisine

Thomas Keller- The French Laundry

Jose Andrews- A Taste of Spain in America

 Eric Ripert- A Return to Cooking

Joel Rubuchon- The Complete Rubuchon